Twenty-eight of the 86 long-term smoke-exposed dogs
(30%) died during the course of the exposures, and the death
rates “paralleled the dosage of tar and nicotine.” The principal
causes of death reported were pulmonary edema, bronchial
pneumonia, pulmonary brosis, emphysema, and cor pulmonale.
At necropsy, bronchiolo-alveolar tumors were found
in 16 of the 28 mortalities: 12 noninvasive tumors and 4 in